Why do men get hard when they see women?

In fact, the penis erection is called the penis erection. There are three mechanisms for the erection of the male penis. The first is sexual desire, that is, there is a desire. If there is no desire, it cannot be erected. First of all, there must be a desire to stimulate. The second is that there must be a very good heart function, that is, after the erection, the blood pumped out by the heart must be very strong. The third is the time it takes to maintain the erection, which requires the maintenance of kidney essence.

Erection Principle

The corpus cavernosum is composed of smooth muscle cells and connective tissue. The corpus cavernosum nerve has two components, sympathetic and parasympathetic. The former comes from spinal cord T11 to L2, and the latter comes from spinal cord S2-4. Stimulating the sacral sympathetic nerve can cause penis enlargement, while stimulating the thoracolumbar central nerve can cause penis flaccidity. The dorsal penis nerve transmits sensations to the penis body and glans skin, as well as the urethral opening and corpus cavernosum.

Genital erection is a complex psychological state-physiological process, which is essentially a series of neurovascular activities.

Hardness level

Normal: Sexual desire is normal, erection is quick, erection lasts long enough to cause the man to ejaculate or disappear after sexual intercourse is terminated, penis can be inserted into the vagina at will, sexual sensation is good, there is no significant change in the frequency of sexual intercourse, and erection during masturbation is normal.

Ⅰ° (mild): sexual desire is basically normal, erection response is fast, erection duration is unstable, sometimes it cannot last, penis hardness sometimes cannot be inserted into the vagina (one or two times is normal, no such exception), sexual sensation is basically normal, sexual life frequency is less than before, masturbation erection response is basically normal. This level of erectile dysfunction is usually caused by short-term psychological stimulation, as long as the mind is enough to adjust the mood, it can be self-healing. Readers are expected to objectively judge this point to avoid unnecessary anxiety.

II° (mild to moderate): sexual desire becomes weaker, erection response slows down, and often cannot be sustained, the penis is often too hard to penetrate the vagina, sexual sensation disappears, the frequency of sexual intercourse decreases significantly, and the erection response during masturbation is sparse.

III° (moderate to severe): Sexual desire is completely reduced, there is no erection response, and the penis cannot be kept erect for a long time. The penis cannot penetrate the vagina at all and there is no sensual sensation.